Protestors rally after being blocked from entering the Golden Bauhinia Square at Hong Kong Convention and Exhibition Centre for the National Day flag raising ceremony Oct. 1, 2014. (Chris Stowers/McClatchy) McClatchy

Protestors rally after being blocked from entering the Golden Bauhinia Square at Hong Kong Convention and Exhibition Centre for the National Day flag raising ceremony Oct. 1, 2014. (Chris Stowers/McClatchy) McClatchy

How long will Beijing let Hong Kong pro-democracy protests go on?

China’s Communist Party seems determined to snuff out any “contagion” from Hong Kong’s lively pro-democracy demonstrations reaching the mainland.

In the days since protests broke out in the former British colony, at least a dozen mainland activists have been detained, and others threatened, for activities supporting the protests, a human rights group said Wednesday. China has intensified its censorship of the Internet, apparently to prevent news and photos of the protests from going viral across the mainland.

Ironically, many of Hong Kong’s protest and civic leaders don’t want to be seen as spreaders of contagion, since it might give Beijing just one more reason to use its paramilitary forces to end the demonstrations.

“It’s a very scary situation, because China has a history of overreacting in its use of force,” said Michael C. Davis, a professor of law at the University of Hong Kong. He thinks China’s leaders would intervene militarily only if they thought the Hong Kong protests truly threatened their hold on power. At the moment, they apparently don’t.

Wednesday was China’s National Day in Hong Kong and the mainland, a day to honor the nation’s war dead and show patriotism to the homeland. In China, state television displayed images of elaborate choreographed ceremonies in Beijing’s Tiananmen Square, the site of a bloody 1989 crackdown on student protesters.

It was less of a spectacle in Hong Kong, where relatively few people showed up at the city’s annual public ceremony, in Victoria Park, compared with previous years, according to local media reports. By contrast, tens of thousands of people converged on pro-democracy protest sites in at least four points of Hong Kong. The crowds were small in the morning, but, following a familiar pattern, they grew into a mass convergence – part protest, part street festival – into the evening.

At each site, vast message boards carried protesters’ thoughts about the demonstrations, in Chinese and other languages. People took to stages to give two-minute speeches venting their frustrations. At night, against a backdrop of skyscrapers, protesters held up their glowing mobile phones to create many thousand points of light.

For a crowd that’s mostly young – in their 20s and 30s – it’s all very exciting. But protest organizers are quick to remind people that a police response could come at any moment.

China watchers are divided on the likelihood that Beijing would use force to shut down the protests. Last weekend, local police used tear gas and pepper spray on the demonstrators; the crackdown succeeded only in drawing more people to protest.

Orville Schell, the director of the Asia Society’s Center on U.S.-China Relations, reminded in a televised interview that “nobody could quite believe that China would send troops in” to crush the Tiananmen student protests in 1989. “But they did,” he said.

Speaking on the “Charlie Rose” show, Schell said there was an “extremely dangerous prospect” that Beijing might move to quash the students in Hong Kong.

Nicholas Bequelin, another longtime China watcher who appeared on the program, disagreed. Bequelin, a researcher for Human Rights Watch, said the Communist Party didn’t appear to feel threatened at the moment. As a result, he said, it probably won’t aggressively act against Hong Kong “if there is no contagion of protest in China.”

Beijing seems to be working to prevent that possibility. On Wednesday, the organization Chinese Human Rights Defenders reported that China had detained a dozen activists who’d voiced their support for the Hong Kong protests in recent days. One in Shenzhen, near south China’s border with Hong Kong, had posted messages online about the protests. Another, in Shanghai, had shaved her head in solidarity with the protesters and posted an image online, according to the human rights group.

Even in normal times, Chinese authorities closely monitor and filter the few social media sites that aren’t completely blocked on the mainland, such as Facebook and Twitter. But in recent days, Weibo, China’s version of Twitter, has been closely scrubbed of photos and comments that pertain to the Hong Kong demonstrations. State media on the mainland, meanwhile, have provided little coverage of the mass protests, other than editorials dismissing the unrest as the work of foreign influences.

At issue in Hong Kong is Beijing’s plan, announced two months ago, for how the territory’s residents will vote for a chief executive in 2017. While the territory’s pact with China promises Hong Kong a “high degree of autonomy,” Beijing has insisted on a system in which a committee of loyal party backers chooses which candidates will be on the ballot.

In editorials and commentaries in the last week, Chinese state media have tried to make the case that Hong Kong’s protests are small and fomented by activists whose ultimate goal is a complete break with China.

Asked about that Wednesday, a leading Hong Kong politician and activist, Albert Ho Chun-yan, shook his head, saying Beijing’s claims are “totally groundless.” Protesters, he said, want China and Hong Kong’s governments to honor the promise of autonomy made when the British agreed in 1984 to turn over the territory.

Davis, the law school professor, said it was important for Beijing and the world to understand that protesters weren’t seeking complete independence from China, just the “high degree of autonomy” promised under an international agreement.

Young Hong Kong protesters attempted to send that message Wednesday. They offered yellow ribbons to tourists from the mainland. A banner along a closed thoroughfare read, “We are asking for Democratic Elections ONLY!”

Davis said the unstructured nature of the protests might make it hard for Beijing to agree to concessions. The mass demonstrations include a variety of civic and student groups, with even high schoolers playing key roles.

On Wednesday evening, local media reported that student leaders have insisted that Hong Kong’s leader, Chief Executive Leung Chun-ying, who’s also known as C.Y. Leung, resign by Thursday. If he doesn’t, students have vowed to occupy government buildings, the kind of action that prompted tear gas last weekend.

“The protesters don’t have a real leadership structure,” said Davis. “But they have to make choices. Do they stay in one place? Go home? Come back? How far do they go with their tactics?”

Hong Kong's main business district continues to be brought to a standstill by mass crowds of pro-democracy student protestors and ordinary Hong Kong citizens Oct. 1, 2014. (Chris Stowers/McClatchy) McClatchy

Well-organized and unfailingly polite, students help fellow supporters over a road barrier into the main protest area near government buildings in Hong Kong's main business district, which continues to be brought to a standstill by mass crowds of pro-democracy student protestors and ordinary Hong Kong citizens Oct. 1, 2014. (Chris Stowers/McClatchy) McClatchy

Pro-democracy protests in Hong Kong move from the central business district to Kowloon peninsula. Here protestors continue their blockade of the main Nathan Road/Argyle Street intersection Oct. 1, 2014. (Chris Stowers/McClatchy) McClatchy

A makeshift barrier stops all traffic along Kowloon's main thoroughfare, Nathan Road. Pro-democracy protests move out from the central business district to Kowloon peninsula Oct. 1, 2014. (Chris Stowers/McClatchy) McClatchy

Protestors rally after being blocked from entering the Golden Bauhinia Square at Hong Kong Convention and Exhibition Centre for the National Day flag raising ceremony Oct. 1, 2014. (Chris Stowers/McClatchy) McClatchy

Two men take a break on a blockaded road near the main protest site where demonstrators have taken over the Admiralty district of Hong Kong on Oct. 1, 2014. The sign next to them reflects how protesters are trying to make clear to Beijing that their democracy goals are limited, and do not involve a complete break from the mainland. (Stuart Leavenworth/McClatchy) McClatchy

Protestors rally after being blocked from entering the Golden Bauhinia Square at Hong Kong Convention and Exhibition Centre for the National Day flag raising ceremony Oct. 1, 2014. (Chris Stowers/McClatchy) McClatchy

Hong Kong's main business district continues to be brought to a standstill by mass crowds of pro-democracy student protestors and ordinary Hong Kong citizens Oct. 1, 2014. (Chris Stowers/McClatchy) McClatchy

Hong Kong's main business district continues to be brought to a standstill by mass crowds of pro-democracy student protestors and ordinary Hong Kong citizens Oct. 1, 2014. (Chris Stowers/McClatchy) McClatchy